TOPIC:

Once done you can RIDE THE PISS OUT OF IT like me.
Steve

Sheath wrote: ...what the hell happened to that Rod too?!!

Same thing happened to my push rod in 2015. At the time this pic was taken I had the gear case off just to replace the badly-leaking gasket. I didn't even pull the rod out to examine it.
When viewing this pic some time later, there it was! Duh...




Five months later...
I think the entire r&r process took about one forth the time. I replaced the severed rod with an APE one-piece clutch rod, which I believe is hardened steel.



With regard to your broken off shaft/nut, the recommendation to have it welded in-place makes perfect sense, or otherwise it will have to be replaced.

Oh yeah ! I can see how the rod was wearing thin on yours, that must be exactly what happened to mine!! I do like the idea of welding although I do worry about heat damaging things around it maybe??

Your Dad is right.

That big nut shearing off is normal for the ST. I know it sounds like a joke, but my buddies ST had the same problem (but not the clutch push rod issue). We researched it and found many/most ST models had the nut break off. People ride for many years that way. It makes a slight clicking noise when going slow, which is the nut falling down in the housing. At speed I think it just stays put from spinning with the coupling, at least it doesn't make a rattle that you can hear over the motor and exhaust.

Some say to fix it, some say to leave it. Most agree if you fix it by replacing the shaft, it will probably break off again.

It is weird that it breaks off at all. Not sure what is going on inside the coupling that would cause that. Were they all over-torqued at the factory? Was there a quality issue with the shaft? We never figured it out. I think my buddy just removed the nut. He rode it like that for a few years. Eventually he took the bike apart since his plan was always a chain conversion with bigger swingarm etc.

I wish I knew more about this specific bike to help out a bit, but I have never owned or worked on one. Through this entire thread it sounds like Kawasaki really dropped the ball here. Suggesting that the OP replace the broken parts only to have it happen again is a non-starter for me anyway. In my estimation it would either be a strip it and sell the parts or sell the bike as is. Not sure how much it would cost to repair this issue but if the OP can't do it himself he is just throwing good money after bad. Don't mean to throw water on anyone's parade, but even if it was properly repaired returning breakage would always be in the back of my mind. If this wasn't a fault of Kawasaki design engineers then it was planned obsolescence. In either case none of this is acceptable.
Rick H.

If the nut is a common breaking point I would probably just weld the shaft or do the chain conversion. No sense in investing in something that is likely to break again. Maybe if you decided to full resto and not ride it daily it would make sense.

I'd repair it then torque it to 50 and see if that helps. On the Z1 it's 100 PSI and in the book the ST is 80. A 630 chain may need it where a shaft wouldn't. Or you could tack weld it and RIDE THE PISS OUT OF IT.
Steve

Thanks for all the thoughts and suggestions guys, I'm stuck between a rock and a hard place with this bike, in the 5 years I've owned it I've put so much into it that I have real emotional attachment, see the before and after pics, apart from paint and exhausts etc I've changed.....the rear shocks, handlebars,grips, footrests, lots of rubber bungs and chrome washers, the headlight the name plate across the forks, coil packs, fuse box, battery, horn, I've fixed a collapsed top cam chain sprocket, fixed 3 oil leaks, made three helicoil repairs, changed wheel bearings, front brakes rebuilt, rear brake rebuilt, braided lines, genuine kawasaki clutch and cable,tacho cable,clock bulbs replaced, 4 airbox to carb rubbers (genuine) 4 cam end plugs (genuine) ht leads and caps,plugs, set up the carb float heights and balanced them, had all the valve shims checked and adjusted ,cleaned old rust out of the fuel tank, repaired tears in the seat, made a seat stay and all this is only over 8000 miles!! But I'm not really a mechanic, only an enthusiast and I think this time I'd like to hand it over to a good engine builder and maybe at the same time get the glaze busted on the bores and new rings because when I had the valve shims done although it improved compression across the cylinders, cylinder number 2 was 25psi down but shot up with a small amount of oil down the spark plug hole, that was 2 years ago and it always bothers me I've started looking at prices for the output shaft replacement and the bore job and it looks like it'll be around £450 for the first and £500 for the latter or $1240 ! I think I would ask with a new shaft for the nut to maybe be welded to the washer? Or perhaps not torqued so much?? It's a lot of money but on the other hand my bike does mean a LOT to me if you guys know what I mean!

The link I put up isn't nearly that much. I'd buy it and torque it at a lower setting. I bought my bike new in 75. With the wreck and all it's not the same but it's mine and I love it. That's all that matters. There have been a few members that couldn't buy from the states so a member here and there bought it and sent it to them. It's up to you but if it were me I'd fix it and keep it.
Steve

Hey Steve, yes I definitely don't want to sell the bike I just have to decide ,do I take the engine out and attempt to fix it myself, or take the whole bike to a garage. ....
Either way it's tough ,apart from cost and time I haven't ridden it in six weeks!

All said and done it took me a week.
Steve

Hey Sheath, does that crescent shaped fracture align with where the nut was staked?
If so, maybe that is the problem causing this issue, it certainly looks like a shock fracture to me.
Can you confirm.
Cheers.